In July of 2015, Idexx Laboratories began offering an in-office, ten-minute test that is designed to tell your veterinarian if leptospirosis is the cause of your pet's illness. That is an important advancement because, until now, the tests had to go to a central lab. It could take up to a week for the test results to get back to your veterinarian.
There were three types of tests:
One attempted to grow living leptospira from the sample submitted from your pet (culture). Leptospira organisms are hard to grow – particularly after the first few days of illness or if the pet had already received antibiotics.
The second test looked for antibodies in the pet’s blood directed against leptospira – evidence the organism was or had been present. Weak positive tests could be quite hard to interpret and negative early in the disease before the pet has time to produce antibodies. Some weak-positive tests could have been from a previous vaccination.
The third test looked for the signature proteins (antigens) of the leptospira organisms in the sample submitted (PCR test). When the PCR test was positive, we knew the dog had active leptospirosis. But some infected dogs had lepto antigens at too low a level to be detected by PCR - either very early in the disease or after receiving antibiotics. And like the first two tests, waiting to getting the lab report back sometimes delayed specific treatment.
This new, fourth test option should let your veterinarian begin treatment immediately. The sooner the right antibiotics are given, the more successful the treatment tends to be. The symptoms of leptospirosis are quite variable and can easily be confused with other illnesses. If this test is run, it lets your vet choose the best antibiotics for lepto. If he/she doesn’t know for sure what they are treating, an antibiotic that is less effective or ineffective might have been chosen.
You can read the most current treatment suggestions I have here. Leptospirosis-exposure is a danger to the owners, hospital staff and other pets in the family. This test should alert everyone to that threat early on.
The test is new on the market and things are rarely perfect. We will not know how well it performs until veterinarians have more experience using it. But Idexx has an excellent track record regarding the quality of the products they produced. One major concern will be how to interpret the results in a dog that had been previously vaccinated against leptospirosis. The Company acknowledges that some of those dogs – particularly those with a recent leptospirosis vaccination - may be positive on the test without an active leptospirosis infection. Also, how long that post-vaccination, false-positive might last is debatable. That same potential problem applies to all but the PCR and Lepto Isolation (culture) tests performed at a central laboratory.